Web folding apparatus and method

ABSTRACT

An apparatus and method for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack. The webs are interfolded through the use of a plurality of folding devices which are positioned along the path of the stack and are effective to successively turn a longitudinally extending edge portion of each web over the stack. A single folding device is provided for each pair of webs to be interfolded, and the webs in each pair are received by the corresponding folding device at spaced locations along its length. The folding devices are of identical construction and include longitudinal guide elements for preventing the turning over of an edge portion of the web received at the first location until after it has moved past the succeeding location. An angularly disposed guide element on each folding device thereafter turns the edge portion over the stack. An edge portion of the second web received by the folding device is not turned over until the web passes the first location on the immediately succeeding folding device and is received by an additional angularly disposed guide element thereon.

United States Patent Murphyet al.

[54] WEB FOLDING APPARATUS AND METHOD [72] Inventors: James A. Murphy, Camarillo, Calif; Charles A. Lee, Knoxville, Tenn.; Eduarda Spravnlks, Weston, 0ntario,Canada i [73] Assignee: International Paper Company, New

York, N.Y.

[22] Filed: Nov. 23, 1970 [21] Appi. No.: 91,711 I Related 1.1.8. Application Data [63] Continuation-impart of Ser. No. 737,034, June 14,

1968, Pat. No. 3,542,356. 1

52 us. (:1 ...21o/4o I 51 Int. Cl. .assn 45/22' 58 Field of Search ..270/40, 41, 86, 73

[56] References Cited UNITED STATES PATENTS 3,472,504 10/1969 Murphy et al. ..270/40 3,542,356 11/1970 Murphy et a1. ..270/40 Primary Examiner-Lawrence Charles Attorney-Lee C. Robinson, Jr.

[ 51 Dec. 26, 1972 5 7] ABSTRACT An apparatus and method for forming longitudinal folds in a series of webs while interfoiding the webs into a continuously moving stack. The webs are interfolded through the use of a plurality of folding devices which are positioned along the path of the stack and are effective to successively turn a longitudinally extending edge portion of each web over the stack. A single folding device is provided for each pair of webs to be interfolded, and the webs in each pair are received by the corresponding folding device at spaced locations along its length. The folding devices are of identical construction and include longitudinal guide elements for preventing the turning over of an edge portion of the web received at the first location until after it has moved past'the succeeding location. An angularly disposed guide element on each folding device thereafter turns the edge I portion over the stack. An edge portion of the second web received by the folding device is not turned over until the web passes the first location on the immediately succeeding folding device and is received by an additional angularly disposed guide element thereon.

23 Claims, 19 Drawing Figures PATENTEB DEC 2 s 1972 SHEET 2 [IF 4 PATENTEDBEBZB m2 3,707,281

SHEET 3 [IF 4 l WEB FOLDING APPARATUS AND METHOD CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of copending application Ser. No. 737,034, filed'lune 14, 1968, by James A. Murphy, Charles A. Lee and Eduards Spravinks, now U.S. Pat. No. 3,542,356 granted Nov. 24, 1970.

BACKGROUND OF THE INVENTION Although the present invention, is useful wherever a stack or package of interfolded webs is required,-one particularly advantageous use is in the facial tissue field. Such tissue commonly is interfolded by building up a long stack from a large number of separate tissue webs, one for each sheet of tissue in the package. As the webs are assembled in the stack, they are interfolded by a series of folding devices to produce one or A further object of the invention is to provide web folding apparatus utilizing comparatively simple mechanical elements which is economical to manufacture and thoroughly reliable in operation. I

In one illustrative embodiment of this invention, there is provided an apparatus and method for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, The webs are directed in pairs from suitable supply rolls to a pluralityof folding devices which are disposed at spaced intervals along the path of the stack, with a single folding device being provided for each pair of webs. The folding devices are operable to interfold, the webs by successively turning a longitudinally extending portion of each web over the stack. The thus interfolded stack is cut to appropriate lengths for packaging and delivery more longitudinal folds in each web. The assembled stack is 'cut off into convenient lengths which are'then packaged in wrappersor paperboard boxes of a size suitable for use by the consumer. For a more detailed discussion of representative known techniques for interfolding the webs into the stack, reference may be had to Teall U.S. Pat. No. 2,642,279.

Heretofore, difficulties have been encountered in the inter'folding of a succession of webs into a long stack. As an illustration, in many machines previously employed for this purpose a longitudinal edge portion of at least some of the webs was folded underneath the remaining edge portion of the web. The underfolding of the webs involved unnecessary handling and often produced a tendency to form'unwanted creases and wrinkles, particularly when performed by such structural components as folding boards, rods or other elements having comparatively sharp folding edges. Difficulties of this character were of specialmoment-in machines in which a previously formed fold in a given web was opened in order to insert an edge portion of a succeeding web therebetween. Still additional difficulties arose because of the need, in certain prior machines, for utilizing different types of folding devices depending upon whether it was desired to produce a left-hand fold or a right-hand fold in a particular web. The folding devices used heretofore often were of unnecessarily complicated construction which resulted in a further increase in the already high cost of the machine.

SUMMARY One general object of this invention, therefore, is to provide a new and improved apparatus and method for interfolding a succession of webs.

More specifically, it is an object of this invention to provide such apparatus and method in which the underfolding of all of the webs is avoided.

Another object of this invention is to provide an ap paratus and method of the character indicated in which a longitudinally extending portion of each web is interfolded into a stack of webs without the necessity for opening a previously formed fold.

Still another object of this invention is to provide interfolding apparatus in which the individual folding devices need not be of different construction from one device to another.

to the purchaser.

' In accordance with one feature of several advantageous embodiments of the invention, each folding device includes a guide element which positively prevents the turning of a longitudinally extending por tion of a given webover thestack until after the immediately succeeding web has been received. The arrangement is such that there is no necessity for completing the fold in the given web and then reopening that fold in order to insert-the succeeding web therein.

In accordance with another feature of the invention, in certain preferred embodiments, a single folding device is provided for each pair of webs to be interfolded, and the webs in each pair are received by the received by that device. The longitudinally extending portion of this latter web is not completely turned over the stack until it reaches the approximate midpoint of the immediately succeeding folding device. With this arrangement, the handling of the webs is further reduced, and a corresponding reduction is realized in the incidence of unwanted creases and wrinkles.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention, as well as further objects and features thereof, will be understood more clearly and fully from the following description of a preferred embodiment, when read with reference to the accompanying drawings, in which:

FIG. 1 is a top plan view of a folding device for interfolding a pair of facial tissue webs into a stack of webs in accordance with an illustrative embodiment of the invention;

FIG. 2 is a side elevational view of the folding device as seen from the line 22 in FIG. 1;

FIG. 3 is a bottom view of the folding device shown in FIGS. 1 and 2;

FIG. 4 is a top plan view, as seen from the line 4-4 in FIG. 5, of successive facial tissue webs as they are interfolded into the stack, .with portions of the folding devices therefor shown in phantom lines;

. FIG. 5 is a side elevational view of the webs shown in FIG. 4;

FIGS. 6, 7 and 8 are vertical sectional views respectively taken along the lines 6-6, 7-7 and 8-8 in FIGS. 4, showing the progressive inter-folding of the webs, with the fully interfolded positions of the webs illustrated by phantom lines in FIG. 8;

FIG. 9 is a fragmentary elevational view of the inteed end of the folding device, as seen from the line 9--9 in FIG. 1; I

FIGS. 10, 11 and 12 are fragmentary vertical sectional views respectively taken along the lines 10-10, 11-11 and 12-12 in FIG. 1; f

FIG. 13 is a fragmentaryelevational view of the outfeed end of the folding device, as seen from the line 13-13 in FIG. lian'd FIGS. 14-19 are fragmentary vertical sectional views respectively taken along the lines 14-'14 to 19-19 in FIG. 2, together with the corresponding webs as they are interfolded into the stack.

DESCRIPTION OF A PR FERRED EMBODIMENT Referring to FIGS. 1-3 of the drawings, there is shown a folding device 25 in accordance with an illustrative embodiment-of the invention. A series of folding devices, each identical to the device 25; is disposed along a feed path defined by a continuously moving stack of webs to be interfolded. The direction of movement of the stack of webs is indicated in the drawings by the arrow 26. The folding devices are maintained in spaced-apart relationshipwith each other along the length of the stack and are suspended from upstanding rectangular columns 27. it

Each of I the folding devices 25 includes a plate member 30 (FIG. 11) of generally U-shaped cross section. The member 30 extends in a longitudinal direction along the path of the stack of webs and has lower and upper rectangular plates 32 and 33, respectively, which are interconnected by a bight 34. The support column 27 is located at the approximate midpoint of the folding device 25 and is affixed to the upper plate 33. The lower plate 32 extends for an appreciable distance on both the infeed side of the folding device 25 (to the left of the column 2'7, as viewed in FIGS. 1-3) and the outfeed side of the folding device (to the right of the column 27, as viewed in these figures). The upper plate 33, on the other. hand, extends primarily on the outfeed side of the folding device. The bight 34 is disposed between the plates 32 and 33 and also along the exposed longitudinal edge of the plate32 to form an upstanding flange.

Two pairs of guide rollers 36 and 37 are respectively supported along the infeed edges of the plates 32 and 33. The rollers 36 and 37 are mounted for rotation about horizontal axes in position to direct respective webs of sheet material to the plates 32 and 33 in a manner that will become more fully apparent hereinafter.

An intermediate plate 40 is disposed between the plates 32 and 33. The infeed edge of the late 40 is-coextensive with that of the plate 33, while the outfeed edge is'located a short distance to the left, as viewed in FIGS. 1 3, of the corresponding edge of the plate 33.

As best shown in FIG. 11, the plate 40 is welded or otherwise rigidly secured along one of its longitudinal edges to the bight 34. The plate 40 protrudes from between the plates 32' and 33 and is bent to form an upstanding flange 41. The flange 41 terminates in a longitudinal edge 42 which is tapered in the manner shown in FIG. 2. The arrangement is such that the height of the edge 42 with respect to the stack of webs gradually increases in the direction of movement of the stack.

Affixed to the exposed upper surface of the lower plate 32 are two strap members 45 and 46. The members 45 and 46 support a guide plate 47 which extends at a small acute angle with respect to the direction of movement of the stack. As best shown in FlGS. 9 and 10, the plate 47 is disposed in a horizontal plane which is located a short distance above the planeof the plate 32 to form a tissue receiving slot 48 therebetween. The inner portion50, of the plate 47 is bent upwardly and is provided with a gradually decreasing taper in the direction of movement of the stack. The infeed end of I the plate 47 is located immediately adjacent and to one rollers 37. The outfeed end of the plate 47 terminates a ly one half way between the guide short distance before the outfeed end of the plate 32.

The" upwardly extending portion 50 of the plate 47 is in spaced relationship with an L-shaped guide member 52. The member 52 is rigidly mounted on the upper surface of the plate 32 and includes an upstanding flange 53 in facing relationship with the portion 50. The flange 53 is provided with a gradually'decreasing taper which is similar to the taper on the portion 50, and the space between the portion 50 and the flange 53 forms a vertically disposed extension of the tissue receivingslot 48. An angle member 55 is affixed along one leg to the vertical portion of the flange 53 and along the other leg to the lower surface of the intermediate plate 40 thereabove. The members 52 and 55 are oriented at an acute angle with respect to the direction of movement of the stack of webs in a manner similar to the angular disposition of the guide plate 47.

The infeed end of the flange 53 includes a rectangular extension 57. The extension 57 is bent so that it lies in a plane parallel to the direction of movement of the stack and is disposed on the infeed side of the guide rollers 36. The flange 53 and the associated angle member 55 extend from adjacent the rollers 36 into the space between the plates 32 and 40. The outfeed ends of the guide member and the flange are located approximaterollers 37 and the outfeed edge of the plate 32.

ln a generally similar manner, a second angularly disposed guide plate 60 is supported above the upper plate 33 by two strap members 61 and 62. The plate 60 I is maintained in spaced relationship with the plate 33 to form a tissue receiving slot' 64 (FIGS. 12) therebetween. The inner portion 65 of the plate 60 is bent in an upward direction, and its upper longitudinal edge is provided with a gradually decreasing taper in the direction of movement of the stack of webs.

A guide member 66 of L-shaped cross section is rigidly afiixed to the upper surface of theplate 33. The member 66 includes an upstanding flange 67 which is 10501 v (run tension 70 is disposed immediately adjacent the'outfeed side of the guide rollers 37 in a plane parallel to the direction of movement'of the stack. From the point at which the extension 70 meets the flange 67, the flange 67, the guide member 66, the angle member 68 and the guide plate 60 proceed diagonally across the plate 33. at a fairly large obtuse angle with respect to the direction of movement of the stack. The outfeed ends of these components are located a substantial distance beyond the outfeed edge 'of the plate 33.

A series of the folding devices 25, one for each pair of webs to be interfolded into the stack, is disposed along the feed path of the stack with the individual folding devices in spaced-apart relationship with each other. As shown in phantom lines in FIGS. 4 and 5, for example, a first foldingdevice 250 is arranged to received two webs 75a and 75b, and a second folding device 25b likewise is arranged to receive two webs, one of which is shown at 750. The webs for each folding device are received at succeeding locations along the path of the stack which respectively correspond to the locations of the spaced sets of guide rollers 36 and 37. In addition, the folding device 25a receives still another web 75d from. the immediately preceding folding device.

Each of the various webs to be interfolded includes a pair of longitudinally extending edge portions which are arrayed on opposite sides of a median or V fold 77. Thus, the web 75a includes longitudinally extending edge portions 7501 and 75a2, the web 75b includes longitudinally extending edge portions 75bl and 75b2, and so on. In the illustrated embodiment, the edge portions of each web extend in transverse cross section continuously from the midpoint of the web to the outer edges.

However, other embodiments of the invention readily may be adapted for the formation of so-called Z folds for example, in which case the longitudinally extending portions on opposite sides of the fold do not necessarily extend to the edges of the web.

As more fully described in Pherson et al. US Pat. No. 3,285,599 and Murphy et al. US. Pat. No. 3,472,504, the pairs of webs are advanced toward the folding devices from individual supply rolls located adjacent the path of the stack. The supply rolls for each pair of webs, such as the webs 75a and 75b, may be supported one above the other on a suitable frame (not shown herein but illustrated in the Pherson et al. and Murphy et al. patents) which also carries the support columns 27. In some embodiments the axes of the supply rolls and the individual folding devices are maintained in stationary positions during the interfolding operation, while in other cases the supply rolls and folding devices are directed along a closed path countercurrent to the direction of movement of the stack. The webs in each pair are withdrawn from the rolls in contact with each other and in substantially unfolded condition. As each pair of webs approaches the corresponding folding device, the webs diverge away from each other toward the respective guide rollers 36 and 37 on the device.

The web 75a is received by the guide rollers 36 at the infeed end of the folding device 25a. The edge portion 75a1 of the web 75a is directed along one side of the feed path for the stack of webs, while the edge portion 75a2 passes around the rollers 36 and is laid onto the stack in facing contact with the edge portion 75d1 of the web 75d from the immediately preceding folding device.

As best shown in FIGS. 14-16, as the web 75a moves along the folding device toward the upstanding column 27, the edge portion 75a2 is disposed immediately beneath the lower plate 32. During this portion of the movement of the web 75a, the remaining edge portion 75a! is carried into contact with the guide flange or bight 34. The bight 34 cooperates with the extension to positively prevent the turning of the edge portion a1 over the stack of webs until after the web 75a has moved past the guide rollers 37 (FIG. 2) and approaches the position shown in FIG. 17.

Upon further movement of the web 75a, the edge portion 75al enters tissue receiving slot 64 and is gradually turned over the path of the stack by the angularly disposed guide plate 60. At the time the web 75a nears the outfeed end of the folding device 25a and reaches the position shown in FIG. 19, the turning over of the edge portion 7501 is substantially complete, and the web 75a moves along the path of the stack in interfolded relationship with the adjacent webs.

The folding device 25a additionally is arranged to turn over the longitudinally extending edge portion 75d2 of the web 75d from the immediately preceding folding device. At the time the web 75d reaches the folding device 25a, the edge portion 75dl is located along the path of the stack, while the edge portion 7 5d2 extends upwardly at approximately a right angle with respect to the edge portion 75d1. The edge portion 75d2 is maintained in this position by the extension 57 (FIGS. l-3). The extension 57 serves to positively prevent the turning of the edge portion 75d2 over the stack until after the succeeding web 75a is received by the guide rollers 36. The extension thereupon directs the edge portion 75d2 into the slot 48 (FIG. 14). As the web 75d continues its movement along the folding device 25a, the tapered portion 50 of the guide plate 47 gradually urges the edge portion 75d over the previously laid down edge portion 75d2 of the web 75a, with the plate 32 therebetween. As the web 75d moves between the positions shown in FIGS. 17 and 18, the edge portion 75d2 leaves the slot 48 and is fully turned over the stack in interfolded relationship with the web 75a.

The web 75b is'received by the guide rollers 37 at the approximate midpoint of the folding device 25a. As the web 75b enters the device 25a, the edge portion 74b1 moves around the rollers 37 and into the space between the upper plate 33 and the intermediate plate 40. The remaining edge portion 75b2, on the other hand, is externally disposed with respect to the folding device 25a. Upon continued movement of the web 75b through the folding device, the upstanding tapered portion 41 of the plate 40 engages the edge portion 75b2 and gradually raises the portion 75b2 until it forms a right angle with respect to the remaining edge portion 75b1,

as shown in FIG. 19. The actual turning of the edge portion 75b2 over the stack of webs is positively prevented, however, by the extension 57 on the immediately Succeeding folding device 25b.

lna manner similar to that described above in conthe remaining web (not visible in the drawings) for turning over by a following folding device.

, It will thus be apparent that the various folding devices are operable to interfold the webs into the stack by successively turning a longitudinally extending portion of each web over the stack. The webs are led toward the folding devices in pairs, but the webs in each-pair are received by the corresponding folding device at succeeding locations along the path-of the stack. Each folding device is effectiveto completely turn over an edge portion of one of the webs in the pair, such as the edge portion 72d1 of the web 75a, and to prepare an edge portion of the remaining web, such as the edge portion 75 b2 of the web 75b, for turning over by the immediately succeeding folding device. The turning of an edge portion of each web over the stack is completed prior to the turning over of an'edge portion of the succeeding web. Only a single folding device is provided for each pair of webs to be interfolded, and the underfolding of the edge portions as well as the reopening of a previously folded web have been eliminated.- As a result, the handling of the individual webs is maintained at'a minimum, with a corresponding reduction in the incidence of unwanted creases, wrinkles or web breakage.

Each of the folding devices is of identical construction and is fabricated from sheet steel or other flat structural material. The devices are of comparatively simple configuration and are economical to manufacture. in the large quantities customarily employed in tis sue folding machinery.

The terms and expressions which have been employed areused as; terms of description and not of limitation, and there is not intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described, or portions thereof, it being recognized that various modifications are possible within the scope of the invention claimed.

What is claimed is:

l. in apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, said folding devices having infeed means for receiving successive webs at spaced locations along said patlnhaving web directing means located on the outfeed side of the infeed means for interfolding the webs by engaging a longitudinally extending portion of each web and successively turning said edge portions over said stack, and having guide elements located between the infeed means and the web directing means for preventing the turning over of a longitudinally extending portion of rum each web until after the immediately succeeding web has been received.

' 2. ln apparatus as defined in claim 1, each of said guide elements comprising a substantially flat plate member mounted in a plane parallel to the direction of movement of the stack of webs'along' said path.

3. in apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding devices having infeed meansfor receiving a pair of webs in substantially unfolded condition, said folding devices being operable to 'interfold said webs by successively turning a longitudinally extending portion of each web over said staclgand said folding devices including guide elements located on the outfeed side of the infeed means for engaging a longitudinally extending portion of each web to prevent the turning over of said edge portion until after the immediately succeeding web has been received. I I

4. ln apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding devices having first infeed means for receiving a first web ata first location along said path and second infeed means for receiving a second web at a succeeding location along said path, said first and second webs being received by said folding devices inv'substantially unfolded condition, said folding devices being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack.

5.'ln apparatus for forming longitudinal folds in a se ries of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding devices having first infeed means for receiving a first web at a first location along said path and second infeed means for receiving a second web at a succeeding location along said path, said folding devices-being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack, each said folding device including a guide element for preventing the turning over of a longitudinally extending portion of said first web until after it has moved past said succeeding location and said second web has been received, said guide element being mounted on the folding device between the first and the succeeding locations in position to engage the longitudinally extending edge portion of the first web.

lnmie n-ren means being angularly disposed with respect to the path of said stack. a t

8. ln apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along-the path of said stack in spaced relationship with each other, said folding devices having infeed means for receiving successive webs at spaced locations along said path and being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack, each said folding device including a first guide element located on the outfeed side of the infeed means in position to engage a longitudinally extending portion of a web received at one of said locations and thereby prevent the turning over of said edge portion of the received web 'until after it has moved past the immediately succeeding location, and including a second guide element located on the outfeed side of said succeeding location for thereafter turning said portion of said web over said stack.

9 ln apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding devices having infeed means for receiving a pair of webs in a substantially unfolded condition, said folding devices being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack, each said folding device including a first guide element located on the outfeed side of the infeed means in position to engage a longitudinally extending portion of one of the webs in said pair and thereby prevent the turning over of said edge portion until after the other web in said pair has been received, and including a second guide element located on the outfeed side of the first guide element for thereafter turning said one web over said stack.

l0. ln apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding devices having first infeed means for receiving a first web at a first location along said path and second infeed means for receiving a second web at a succeeding location along said path, said folding devices being operable to interfold said webs by successively turning a longituason dinally extending portion of each web over said stack,

eachfolding device including a first guide element for preventing the turning over of a longitudinally extending portion of said-first web until after it has moved past said succeeding location and said second web has been received, and having a second guide element for thereafter turning said portion of said first web' over said stack, said first guide element being mounted on the folding device between the first and the succeeding locations, and said second guide element I being mounted on the folding deviceon the-outfeed side of the succeeding location.

tinuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path'of said stack in spaced relationship with each other, said folding devices having infeed means for receiving succes sive webs at spaced locations along said path and being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack, each said folding device including a first guide element for preventing the turning over of a longitudinally extendingportion of a first web received at one of said locations until after it has moved past the immediately. succeeding location, including a second guide element-for thereafter turning said portion of said first web over said stack, and including a third guide element for turning a longitudinally extending portion of a second web from the immediately preceding folding device over said stack, said first and third guide elements being mounted on the folding device'between said one location and said succeeding location, and said second folding device being mounted on the folding device on the outfeed side of said succeeding location.

13. In apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding devices having infeed means for receiving a pair of webs in substantially unfolded condition, said folding devices being operable to interfold said webs by successively turning -a longitudinally extending portion of each web over said stack, each said folding device including a first guide element located on the outfeed side of the infeed 1 means for preventing the turning over of a longituguide element for turning a longitudinally extending tending portion of the other web in the pair of webs received by the preceding folding device until after said one web has been received. a g

15. In apparatus for forming longitudinal folds in a series of webs while inte'rfolding the webs into aeontinuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides I of the fold, the improvement which comprises a pluralitty of folding devices positioned along the path of the stack in spaced relationship with each other, a single one of said folding devices. being provided for each pair of webs to be interfolded, each of said folding'devices having first infeed means for receiving a first web at a first location alongsaid path and second infeed means for receiving a second web at a succeeding location interfold said webs by successively turning a longitudinally extending portion of each web. over said stack, each'said folding device including a first guide element for preventing the turning over of a longitudinally extending portion of said first web until after it has moved past said succeeding location and said second web has been received, including a second guide element for thereafter turning said-portion of said'first web over said stack, and including a third guide element for tuming a longitudinally extending portion of the second web from the immediately preceding folding device over said stack,said first guide element extending in a direction parallel to the path of said stack and said second and third guide elements defining web-receiving slots which are angularly disposed with respect to said path, said first and third guide elements being mounted on the folding device between said first location and succeeding location, and said-secondfolding device being mounted on the folding device on the outfeed side of said succeeding location. 16. In a method for forming longitudinal folds in a series of webs while interfolding the webs into a continu ously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the steps of feeding said webs to a plurality of folding devices'positioned along the path of said stack, receiving said webs at succeeding locations along said path, interfolding said webs by successively turning a longitudinally extending portion of each web over said stack, and preventing the turning over of said longitudinally extending portion of each web prior to the interfolding thereof until after the web has been received at one of said locations and has been carried along the continuously moving stack past an immediately adjacent location. v I 17. In a method for forming longitudinal folds in a series of webs while interfolding the-webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the steps of feeding first and second webs to a first folding device positioned along the path of said stack, feeding third and fourth webs to a second folding device positioned along the path of said stack, receiv ing said first, second, third andfourth webs at said foldingdevices in substantially unfolded condition, interfolding said webs by successively turning a longitudinally extendingportion of each web over said stack, and preventing the turning over of said longitudinally extending portion'of each web prior to the interfolding thereof until after the immediately succeeding web has been received.

18. in a method as defined in claim 17, the longitudinally extending portion of said first web being turned over the path of said stack by said first folding device, the longitudinally extending portions of said 1 second and third webs being turned over the path of said stack by said second folding device, and the longitudinally extending portion of said fourth web being turned over the path of said stack by a succeeding folding device.

- 19. In a method for forming longitudinal folds in a series of webs while inter-folding the webs into acontinuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the steps of feeding first and second webs to a first folding device positioned along the path of said stack, feeding third and fourth webs to a second folding device positioned along the path of said stack, receiving said first, second, third and fourth webs at succeeding locations along said path, interfolding said webs by successively turning a longitudinally extending portion of each web over said stack, and preventing the turning over of said longitudinally extending portion of each web prior to the interfolding thereof until after the web has been received at one of said locations and has been carried along the continuously moving stack past an immediately adjacent location.

20. In a method for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the steps of feeding first and second webs to a first folding device positioned along the path of said stack, feeding third and fourth webs to a second folding device positioned along the path of said stack, receiving said first, second, third and fourth webs in substantially unfolded condition at succeeding locations along said path, interfolding said webs during their movement along said path by turning a longitudinally extending portion of said first web over said stack as it moves between the locations for said second and third webs, turning a longitudinally extending portion of said second web over said stack as it moves between the lo- Cations for said third and fourth webs and successively turning a longitudinally extending portion of each of said third and fourth webs over said stack as they move between further locations along said path, and preventing the turning over of said longitudinally extending portion of each web until after the web has been received at one of said locations and has been carried along the continuously moving stack past an immediately adjacent location.

21. A folding device for forming longitudinal folds in a plurality of webs while interfolding the webs into a continuously moving stack of webs, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold,,said folding device comprising means including first and second support members disposed along the path of the stack of webs; first infeed means mounted on the first support member for receiving one of the webs in unfolded condition at a first location along the path; second infeed means mounted on the second support member for receiving another web in unfolded condition at a second location along the path; a pair of substantially flat guide elements affixed to the first-mentioned means and extending in planes perpendicular to the webs in the stack, one of said guide elements being located between said first and second locations in position to engage one of the longitudinally extending portions of said one web and prevent the interfolding thereof as the web moves between said locations, and the other of said guide elements being located on the outfeed side of said second location in position to engage one of the longitudinally extending portions of said other web and prevent the interfolding thereof as the web moves from said second location; and an additional guide element affixed to said second support member on the outfeed side of said second location in position to engage said first web and interfold the same into said stack. I

22 A folding device for forming longitudinal folds in a plurality of webs while interfolding the webs into a continuously moving stack of webs, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, said folding device comprising plate means including first and second rectangular plates extending in spaced relationship with each other in planes parallel to the stack of webs; first infeed means mounted on the first plate for receiving one of the webs in unfolded condition at a first location along the path of the stack; secondinfeed means mounted on the second plate for receiving another web in unfolded condition at a second location along the path of the stack; a pair of substantially flat guide elements affixed to the plate means and extending in planes perpendicular to said first and second plates, one of said substantially flat guide elements being located between said first and second locations in position to engage one of the longitudinally extending portions of said one web and prevent the interfolding thereof as the web moves between said locations, and the other of said substantially flat guide elements being located on the outfeed side of said second location in position to engage one of the longitudinally extending portions of said other web and prevent the interfolding thereof as the web moves from said second location; and an additional guide element affixed to said second plate on the outfeed side of said second location in position to engage said first web and interfold the same into said stack.

23. A folding device for forming longitudinal folds in a plurality of webs while interfolding the webs into a continuously moving stack of webs, each of the webs having a pair of longitudinally extending portions on I the path of the stack; second infeed means mounted on the second plate for receiving another web in unfolded condition at a second location along the path of the stack; third infeed means mounted on the first plate for receiving a third web ad acent said first location; a pair of substantially flat guide elements affixed to the plate means and extending in planes perpendicular to said first and second plates, one of said substantially flat guide elements being located between said first and second locations in position to engage one of the longitudinally extending portions of said one web and prevent the interfoldingthereof as the web moves between said locations, and the other of said substantially flat guide elements being located on the outfeed side of said second location in position to engage one of the longitudinally extending portions of said other web and prevent the interfolding thereof as the web moves from said second location; and a pair of angularly disposed guide elements respectively affixed to said first and second plates and extending at acute angles with respect to the path of said stack, one of said angularly disposed guide elements being located between said first and second locations in position to engage said third web and interfold the same into said stack, and the other angularly disposed guide element being located on the outfeed side of said second location in position to engage said first web and interfold the same into said stack. 

1. In apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, said folding devices having infeed means for receiving successive webs at spaced locations along said path, having web directing means located on the outfeed side of the infeed means for interfolding the webs by engaging a longitudinally extending portion of each web and successively turning said edge portions over said stack, and having guide elements located between the infeed means and the web directing means for preventing the turning over of a longitudinally extending portion of each web until after the immediately succeeding web has been received.
 2. In apparatus as defined in claim 1, each of said guide elements comprising a substantially flat plate member mounted in a plane parallel to the direction of movement of the stack of webs along said path.
 3. In apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding devices having infeed means for receiving a pair of webs in substantially unfolded condition, said folding devices being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack, and said folding devices including guide elements located on the outfeed side of the infeed means for engaging a longitudinally extending portion of each web to prevent the turning over of said edge portion until after the immediately succeeding web has been received.
 4. In apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding devices having first infeed means for receiving a first web at a first location along said path and second infeed means for receiving a second web at a succeeding location along said path, said first and second webs being received by said folding devices in substantially unfolded condition, said folding devices being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack.
 5. In apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding deviCes having first infeed means for receiving a first web at a first location along said path and second infeed means for receiving a second web at a succeeding location along said path, said folding devices being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack, each said folding device including a guide element for preventing the turning over of a longitudinally extending portion of said first web until after it has moved past said succeeding location and said second web has been received, said guide element being mounted on the folding device between the first and the succeeding locations in position to engage the longitudinally extending edge portion of the first web.
 6. In apparatus as defined in claim 5, each of said folding devices including means defining a web receiving slot on the outfeed side of said succeeding location for turning the longitudinally extending portion of said first web over said stack.
 7. In apparatus as defined in claim 6, the slot defining means being angularly disposed with respect to the path of said stack.
 8. In apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, said folding devices having infeed means for receiving successive webs at spaced locations along said path and being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack, each said folding device including a first guide element located on the outfeed side of the infeed means in position to engage a longitudinally extending portion of a web received at one of said locations and thereby prevent the turning over of said edge portion of the received web until after it has moved past the immediately succeeding location, and including a second guide element located on the outfeed side of said succeeding location for thereafter turning said portion of said web over said stack.
 9. In apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding devices having infeed means for receiving a pair of webs in a substantially unfolded condition, said folding devices being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack, each said folding device including a first guide element located on the outfeed side of the infeed means in position to engage a longitudinally extending portion of one of the webs in said pair and thereby prevent the turning over of said edge portion until after the other web in said pair has been received, and including a second guide element located on the outfeed side of the first guide element for thereafter turning said one web over said stack.
 10. In apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding devices having first infeed means for receiving a first web at a first location along said path and second infeed means for reCeiving a second web at a succeeding location along said path, said folding devices being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack, each folding device including a first guide element for preventing the turning over of a longitudinally extending portion of said first web until after it has moved past said succeeding location and said second web has been received, and having a second guide element for thereafter turning said portion of said first web over said stack, said first guide element being mounted on the folding device between the first and the succeeding locations, and said second guide element being mounted on the folding device on the outfeed side of the succeeding location.
 11. In apparatus as defined in claim 10, said first guide element comprising a substantially flat plate member mounted in a plane parallel to the direction of movement of the stack of webs along said path, and said second guide element being angularly disposed with respect to said path.
 12. In apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, said folding devices having infeed means for receiving successive webs at spaced locations along said path and being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack, each said folding device including a first guide element for preventing the turning over of a longitudinally extending portion of a first web received at one of said locations until after it has moved past the immediately succeeding location, including a second guide element for thereafter turning said portion of said first web over said stack, and including a third guide element for turning a longitudinally extending portion of a second web from the immediately preceding folding device over said stack, said first and third guide elements being mounted on the folding device between said one location and said succeeding location, and said second folding device being mounted on the folding device on the outfeed side of said succeeding location.
 13. In apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of said stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding devices having infeed means for receiving a pair of webs in substantially unfolded condition, said folding devices being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack, each said folding device including a first guide element located on the outfeed side of the infeed means for preventing the turning over of a longitudinally extending portion of one of the webs in said pair until after the other web in said pair has been received, including a second guide element located on the outfeed side of the first guide element for thereafter turning said portion of said one web over said stack, and including a third guide element located adjacent the first guide element for turning a longitudinally extending portion of a web from the immediately preceding folding device over said stack.
 14. In apparatus as defined in claim 13, each of said folding devices including a fourth guide element located on the outfeed side of the first guide element for preventing the turning over of a longitudinally extending portion of the other web in the pair of webs received by The preceding folding device until after said one web has been received.
 15. In apparatus for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the improvement which comprises a plurality of folding devices positioned along the path of the stack in spaced relationship with each other, a single one of said folding devices being provided for each pair of webs to be interfolded, each of said folding devices having first infeed means for receiving a first web at a first location along said path and second infeed means for receiving a second web at a succeeding location along said path, said folding devices being operable to interfold said webs by successively turning a longitudinally extending portion of each web over said stack, each said folding device including a first guide element for preventing the turning over of a longitudinally extending portion of said first web until after it has moved past said succeeding location and said second web has been received, including a second guide element for thereafter turning said portion of said first web over said stack, and including a third guide element for turning a longitudinally extending portion of the second web from the immediately preceding folding device over said stack, said first guide element extending in a direction parallel to the path of said stack and said second and third guide elements defining web-receiving slots which are angularly disposed with respect to said path, said first and third guide elements being mounted on the folding device between said first location and succeeding location, and said second folding device being mounted on the folding device on the outfeed side of said succeeding location.
 16. In a method for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the steps of feeding said webs to a plurality of folding devices positioned along the path of said stack, receiving said webs at succeeding locations along said path, interfolding said webs by successively turning a longitudinally extending portion of each web over said stack, and preventing the turning over of said longitudinally extending portion of each web prior to the interfolding thereof until after the web has been received at one of said locations and has been carried along the continuously moving stack past an immediately adjacent location.
 17. In a method for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the steps of feeding first and second webs to a first folding device positioned along the path of said stack, feeding third and fourth webs to a second folding device positioned along the path of said stack, receiving said first, second, third and fourth webs at said folding devices in substantially unfolded condition, interfolding said webs by successively turning a longitudinally extending portion of each web over said stack, and preventing the turning over of said longitudinally extending portion of each web prior to the interfolding thereof until after the immediately succeeding web has been received.
 18. In a method as defined in claim 17, the longitudinally extending portion of said first web being turned over the path of said stack by said first folding device, the longitudinally extending portions of said second and third webs being turned over the path of said stack by said second folding device, and the longitudinally extending portion of said fourth web being turned over the path of said stack by a succeeding folding device.
 19. In a method for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moVing stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the steps of feeding first and second webs to a first folding device positioned along the path of said stack, feeding third and fourth webs to a second folding device positioned along the path of said stack, receiving said first, second, third and fourth webs at succeeding locations along said path, interfolding said webs by successively turning a longitudinally extending portion of each web over said stack, and preventing the turning over of said longitudinally extending portion of each web prior to the interfolding thereof until after the web has been received at one of said locations and has been carried along the continuously moving stack past an immediately adjacent location.
 20. In a method for forming longitudinal folds in a series of webs while interfolding the webs into a continuously moving stack, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, the steps of feeding first and second webs to a first folding device positioned along the path of said stack, feeding third and fourth webs to a second folding device positioned along the path of said stack, receiving said first, second, third and fourth webs in substantially unfolded condition at succeeding locations along said path, interfolding said webs during their movement along said path by turning a longitudinally extending portion of said first web over said stack as it moves between the locations for said second and third webs, turning a longitudinally extending portion of said second web over said stack as it moves between the locations for said third and fourth webs and successively turning a longitudinally extending portion of each of said third and fourth webs over said stack as they move between further locations along said path, and preventing the turning over of said longitudinally extending portion of each web until after the web has been received at one of said locations and has been carried along the continuously moving stack past an immediately adjacent location.
 21. A folding device for forming longitudinal folds in a plurality of webs while interfolding the webs into a continuously moving stack of webs, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, said folding device comprising means including first and second support members disposed along the path of the stack of webs; first infeed means mounted on the first support member for receiving one of the webs in unfolded condition at a first location along the path; second infeed means mounted on the second support member for receiving another web in unfolded condition at a second location along the path; a pair of substantially flat guide elements affixed to the first-mentioned means and extending in planes perpendicular to the webs in the stack, one of said guide elements being located between said first and second locations in position to engage one of the longitudinally extending portions of said one web and prevent the interfolding thereof as the web moves between said locations, and the other of said guide elements being located on the outfeed side of said second location in position to engage one of the longitudinally extending portions of said other web and prevent the interfolding thereof as the web moves from said second location; and an additional guide element affixed to said second support member on the outfeed side of said second location in position to engage said first web and interfold the same into said stack.
 22. A folding device for forming longitudinal folds in a plurality of webs while interfolding the webs into a continuously moving stack of webs, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, said folding device comprising plate means including first and second rectangular plates extending in spaced relationship with each other in planes parallel to the stack of webs; first infeed means mounted on the first plate for receiving one of the webs in unfolded condition at a first location along the path of the stack; second infeed means mounted on the second plate for receiving another web in unfolded condition at a second location along the path of the stack; a pair of substantially flat guide elements affixed to the plate means and extending in planes perpendicular to said first and second plates, one of said substantially flat guide elements being located between said first and second locations in position to engage one of the longitudinally extending portions of said one web and prevent the interfolding thereof as the web moves between said locations, and the other of said substantially flat guide elements being located on the outfeed side of said second location in position to engage one of the longitudinally extending portions of said other web and prevent the interfolding thereof as the web moves from said second location; and an additional guide element affixed to said second plate on the outfeed side of said second location in position to engage said first web and interfold the same into said stack.
 23. A folding device for forming longitudinal folds in a plurality of webs while interfolding the webs into a continuously moving stack of webs, each of the webs having a pair of longitudinally extending portions on opposite sides of the fold, said folding device comprising plate means including first and second rectangular plates extending in spaced relationship with each other in planes parallel to the stack of webs; first infeed means mounted on the first plate for receiving one of the webs in unfolded condition at a first location along the path of the stack; second infeed means mounted on the second plate for receiving another web in unfolded condition at a second location along the path of the stack; third infeed means mounted on the first plate for receiving a third web adjacent said first location; a pair of substantially flat guide elements affixed to the plate means and extending in planes perpendicular to said first and second plates, one of said substantially flat guide elements being located between said first and second locations in position to engage one of the longitudinally extending portions of said one web and prevent the interfolding thereof as the web moves between said locations, and the other of said substantially flat guide elements being located on the outfeed side of said second location in position to engage one of the longitudinally extending portions of said other web and prevent the interfolding thereof as the web moves from said second location; and a pair of angularly disposed guide elements respectively affixed to said first and second plates and extending at acute angles with respect to the path of said stack, one of said angularly disposed guide elements being located between said first and second locations in position to engage said third web and interfold the same into said stack, and the other angularly disposed guide element being located on the outfeed side of said second location in position to engage said first web and interfold the same into said stack. 